Soft decision sections (503, 506) provisionally decide each modulated signal (502, 505) separated using an inverse matrix calculation of a channel fluctuation matrix at separation section (501). Signal point reduction sections (508, 510, 514, 516) reduce candidate signal points of a multiplexed modulated signal using the provisional decision results (504, 507). Soft decision sections (512, 518) make a correct decision using the reduced candidate signal points and obtain received data (RA, RB) of each modulated signal. This allows received data RA, RB with a good error rate characteristic to be obtained with a relatively small number of calculations without reducing data transmission efficiency.

Claim:

The invention claimed is:

1. A multi-antenna transmission apparatus comprising: a first interleaver that generates a third data sequence by interleaving a first data sequence using a firstinterleaving pattern, the first data sequence comprising first transmission data having been encoded, an input order pattern and an output order pattern being different in the first interleaving pattern, and an amount of the first data sequence inputtedinto the first interleaver and an amount of the third data sequence outputted from the first interleaver being the same; a second interleaver that generates a fourth data sequence by interleaving a second data sequence using a second interleavingpattern, the second data sequence comprising second transmission data having been encoded, the second data sequence being different from the first data sequence, an input order pattern and an output order pattern being different in the secondinterleaving pattern, the output order pattern of the second interleaving pattern being different from the output order pattern of the first interleaving pattern, and an amount of the second data sequence inputted into the second interleaver and anamount of the fourth data sequence outputted from the second interleaver being the same; a first modulation section that generates first modulated symbols by modulating the third data sequence; a second modulation section that generates secondmodulated symbols by modulating the fourth data sequence; a first orthogonal frequency division multiplexing conversion section that generates a first orthogonal frequency division multiplexing symbol in which the first modulated symbols are assigned toa plurality of subcarriers respectively; a second orthogonal frequency division multiplexing conversion section that generates a second orthogonal frequency division multiplexing symbol in which the second modulated symbols are assigned to a pluralityof subcarriers respectively; a first transmission section that transmits the first orthogonal frequency division multiplexing symbol from a first antenna; and a second transmission section that transmits the second orthogonal frequency divisionmultiplexing symbol from a second antenna at a common time and in a common frequency band in which the first orthogonal frequency division multiplexing symbol is transmitted, wherein: an amount of data interleaved in the first interleaver is given bymultiplying an amount of all subcarriers used for data transmission in the first orthogonal frequency division multiplexing symbol, by an amount of bits transmitted with one of the first modulated symbols; an amount of data interleaved in the secondinterleaver is given by multiplying an amount of all subcarriers used for data transmission in the second orthogonal frequency division multiplexing symbol, by an amount of bits transmitted with one of the second modulated symbols; and the amount ofdata interleaved in the first interleaver and the amount of data interleaved in the second interleaver are the same.

2. The multi-antenna transmission apparatus according to claim 1, further comprising an encoding section that outputs the first data sequence by encoding part of transmission data as the first transmission data, and outputs the second datasequence by encoding the rest of the transmission data as the second transmission data.

3. A multi-antenna transmission method comprising: using a first interleaver, generating a third data sequence by interleaving a first data sequence using a first interleaving pattern, the first data sequence comprising first transmission datahaving been encoded, an input order pattern and an output order pattern being different in the first interleaving pattern, and an amount of the first data sequence inputted into the first interleaver and an amount of the third data sequence outputtedfrom the first interleaver being the same; using a second interleaver, generating a fourth data sequence by interleaving a second data sequence using a second interleaving pattern, the second data sequence comprising second transmission data having beenencoded, the second data sequence being different from the first data sequence, an input order pattern and an output order pattern being different in the second interleaving pattern, the output order pattern of the second interleaving pattern beingdifferent from the output order pattern of the first interleaving pattern, and an amount of the second data sequence inputted into the second interleaver and an amount of the fourth data sequence outputted from the second interleaver being the same; using a first modulation section, generating first modulated symbols by modulating the third data sequence; using a second modulation section, generating second modulated symbols by modulating the fourth data sequence; using a first orthogonalfrequency division multiplexing conversion section, generating a first orthogonal frequency division multiplexing symbol in which the first modulated symbols are assigned to a plurality of subcarriers respectively; using a second orthogonal frequencydivision multiplexing conversion section, generating a second orthogonal frequency division multiplexing symbol in which the second modulated symbols are assigned to a plurality of subcarriers respectively; transmitting the first orthogonal frequencydivision multiplexing symbol from a first antenna; and transmitting the second orthogonal frequency division multiplexing symbol from a second antenna at a common time and in a common frequency band in which the first orthogonal frequency divisionmultiplexing symbol is transmitted, wherein: an amount of data interleaved in the first interleaver is given by multiplying an amount of all subcarriers used for data transmission in the first orthogonal frequency division multiplexing symbol, by anamount of bits transmitted with one of the first modulated symbols; an amount of data interleaved in the second interleaver is given by multiplying an amount of all subcarriers used for data transmission in the second orthogonal frequency divisionmultiplexing symbol, by an amount of bits transmitted with one of the second modulated symbols; and the amount of data interleaved in the first interleaver and the amount of data interleaved in the second interleaver are the same.

4. The multi-antenna transmission method according to claim 3, further comprising, using an encoding section, outputting the first data sequence by encoding part of transmission data as the first transmission data, and outputting the seconddata sequence by encoding the rest of the transmission data as the second transmission data.